Bed-driving mechanism for power plate presses



Dec. 3, 1929.

A. J. HORTON ET AL BED DRIVING MECHANISM FOR POWER PLATE PRESSES v Filed June 18, 1928 l 1 /M iXI as they approach the turns.

Patented Dec. 3, 1929 UNITED STATES PATENT OFFICE ALBERT J'. HORTON, 0F WHITE PLAINS, AND CHARLES F. GRAVENHORST, OF BROOK- LYN, NEW YORK, ASSIGNORS TO R. HOE da CO., NC., OF NEW YORK, N. Y., A COR- PORATION OF NEW YORK :BED-DRIVING MEGHANISM FOR POWER PLATE PRESSES Application tiled .Tune 18,

The present invention relates to presses used in printing from flat engraved plates, and commonly known as power plate presses. In this class of machines the engraved plates are supported on beds which are moved about in a closed path on ways formed in a'rectangular trame, so as to pass the plates successively under an inking roller, a wiping mechanism and an impression roller. The beds carrying the plates follow a straight path along the sides of the frame and make a right angle turn at each corner. They are usually connected to a chain that is driven by sprockets at each of the four corners of the trame and it has been found that the action oi this chain in passing around the sprockets causes an objectionable lateral motion of the straight portions of the chain which tends to deflect the bases from their normal path, especially Guides have been used to steady` the chain as it engages the sprockets but when they are placed in alignment with the sprocket teeth they do not eX- u tend close enough to the bottom of the sprocket teeth to be eiective, and when they are placed at one side of the sprocket teeth they engage the side links of the chain, whichy being of soft steel are rapidly worn. One member of the cha-in guide that is the subject of the present invention avoids these diiiiculties, as will be hereinafter explained. Another member of the guide herein disclosed is shaped to conform with the outside of the chain as it passes around the sprockets and thus even should the chain be slack it will be held in close engagement with the sprockets and the beds kept in their proper path. 1Were it not for this member a slackness in the chain would permit the beds to travel beyond their proper path in making the turns and strike against the side guides of the frame.

An object of the invention is to provide means for guiding the driving chain of a printing press of the type herein described so that when approaching and leaving the sprockets, the links of the chain will follow lines drawn tangent to the pitch lines oi' the sprockets and there will be-no tendency to deflect the beds from their normal path.

Another object of the invention is to pro- 1928. Serial No. 286,344.

vide a chain guide that will hold the chain` in close engagement with the sprockets when it passes around them.

Still another object of the invention is to provide an arrangement of chain, sprockets and chain guides for a machine of the type herein described, of generally improved construction, whereby the device will be simple, durable, inexpensive in constructionv and practical, seviceable and efficient in its use.

With the foregoing and other objects in view, which will appear as the description proceeds, the invention resides in the combination and arrangement of parts, and in the details of constructions hereinafter described and claimed, it being understood that various changes in the precise embodiment ot the invention herein disclosed may be made within the scope of what is claimed, without departing from the spirit of the invention.

The invention has been illustrated in its preferred embodiments in the accompanying drawings, wherein Figure 1 is a plan view partly broken away showing one corner of a power plate press embodying the invention and illustrating one of the beds at the position where it begins to turn about the sprocket;

Figure 2 is a sectional view partly broken away showing the bed, frame, sprocket, chain and chain guide as viewed on the line A-A. of Figure 1.

Figure 3 is a diagram showing the action oi a chain when its sprocket is not provided with a. chain guide such as is herein disclosed.

Referring to the drawing, this shows a corner portion of a frame work 11 that may be supported. in any suitable manner. It will be understood that there are four such corners to the machine. The bushing 12 is fitted to the trame and forms a bearing for the shaft 13 on the end of which the double sprocket 14 is secured. The shaft is driven by means not shown and the sprocket engages the chain 15 which is thus caused to move along the tour sides of the frame.

W'ays 16 are formed in the frame and serve to support beds, one of which is indicated 17 and to which the engraved printing plate 18 is secured by any suitable means.

At suitable places in the chain 15, studs one of which is shown at 19, are inserted. This stud fits loosely in the bushing 20 which is secured to the bed 17. Side guideways 21 serve lto confine vthe bed .17 although allowing it to move with the chain to which it is connected. By these means the bed is given a travelling movement around the frame and for clearness.

'fao

--the sprocket the :pins ofthe chain will be at .15 :and the 'center line of `the chain Aat 15 `when it engages the sprocket .at l), and the pins will be at andthe center line ofthe chain iat 115 when it engages the sprocket ,ati-P. Inasmuc-h as the beds are connected -tothe chain it will be understood that any sidewise'movemenit of vthe chain would tend to -deii'ectth'ebe'ds from a straighticourse Vand out of engagement with the Yside .guides at those `points where `they are fgni'ded on but one side.

'Guidesh'ave been used vheretofore as shown nin Halliwell Patent No. 1,619,820 to keep the chain on :a line tangent :to the pitch line of the sprocket as the sprocket is approached `but .owing .to their constructions they could not be made to support the chain close enough "to the sprocket to .prevent sidewise motion 4of the chainjust (before it engages the sprockfet. .Afurther objection to .such chain guides .is that vthey bear-against the side links of the chain which are not hardened and consequent- Vlylare rapidly Worn. .The invention herein disclosed :provides means for Yguiding the chain sothat itrapproaches the sprocket on a line that is Vtangent to the pitch line of the 'sprocket at 'all timesand the chain is en- "gaged yon its centre members which are made of hardenedsteel gandare thus protected from ,f The member e2 of ai@ @han guide is fastened to the frame '1'1 by screws 23 and is vformed to occupy ythe space in the groove of the sprocket, passing partly around it and the otherend being fastenedito the Abed 11, by :the-screws 221. It will be understood that by thus guiding :the chain on the inside or sprocketside, it is heldin a path corresponding to the .line 15 of Figure 3 and that the beds are moved forward vin the proper path.

Should fthev chain slacken the momentum fof the beds would tend to carry them too far `when they make the turns and allow them to strike the side guides lunless means is provided to hold the chain in close engagement with the sprocket. The member 25 of the chain guide is secured to the frame 11 by the screws 26 and being shaped to conform to the outside of the chain as it passes around the sprockets constitutes an el'lective means of preventing any over travel of the beds.

It will be seen that an effective means is provided for guiding the chain so that the studs 19 are caused to Vfollow a path correspending to the pitch line of the sprockets and tangent thereto, and that the beds will not be defiected from their path by any side motion of the chain nor allowedto swerve from their true course by any slackness thereof.

l."Vhat we claim is:

1. In a plate printing machine, a frame, a bed, a chain connected to the bed, a sprocket engaging the chain, and a guide member engaging the centre members of the chain and on the inside thereof to keep it in a path vtangent to the pitch line of the sprocket as it engages therewith.

2. In a plate printing machine, a frame, a bed, a chain connected to the bed, a sprocket engaging the chain and having teeth in a plurality of separate axial planes, and a guide member between the separate planes and engaging the chain to keep it in a path tangent to the pitch line of the sprocket as it engages therewith.

3. In a plate printing machine, a frame, a bed, a chain connected to the bed, a sprocket engaging the chain, and a guide member outside the path of the chain and formed to hold the chain in close engagement with the sprocket.

41. In a plate printing machine, a frame, a bed, a chain connected to the bed, a sprocket engaging the chain and a chain guide having members engaging the inside of the chain to keep it in a path tangent to the pitch line ofthe sprocket as it engages the sprocket and a member engaging the outside of the chain to hold itin close engagement with the sprocket.

5. In a plate printing machine, a frame, a bed, a chain connected to the bed, a sprocket engaging the chain, and guide members adjacent to the sprocket and between which the chain passes and is guided to, and around the sprocket.

6. In a plate printing machine, a frame, a bed, a chain connected to the bed, a sprocket engaging the chain, and guide members arranged to act on the inside and outside of the chain where it moves in a curved path.

In testimony whereof, we atlix our signatures.

ALBERT J. I-IORTON. CHARLES F. GRAVENHORST. 

